Abstract: As one of the pivotal technologies in oil and gas field exploration and development, downhole measurement technology provides a scientific basis for reservoir evaluation, drilling optimization, development efficiency improvement, and wellbore operation safety assurance. Compared to traditional cable-based measurements, Measurement While Drilling (MWD) technology can obtain downhole data in real time during the drilling process, accurately control wellbore trajectories, and provide more efficient solutions to address the challenges of exploring and developing unconventional oil and gas fields. This paper mainly focuses on MWD technology, reviewing the latest research progress in drilling data acquisition technology, drilling signal transmission technology, and downhole steering technologies and their instrument systems. It provides a detailed introduction to the workflows, working principles, key components, functional parameters, application scenarios, and performance comparisons of various typical systems, Furthermore, the challenges facing MWD technology and its future development directions are discussed.